The desire for homes that conform to the green building standards of organizations such as Earth Advantage, ENERGY STAR, or LEEDS is growing throughout the world, and nowhere is that more evident than Portland, Oregon. For the fourth straight year in a row, green certified homes have outperformed non-certified homes in the Portland metro region, according to a study by the Earth Advantage Institute.

The desire for homes that conform to the green building standards of organizations such as Earth Advantage, ENERGY STAR, or LEEDS is growing throughout the world, and nowhere is that more evident than Portland, Oregon. For the fourth straight year in a row, green certified homes have outperformed non-certified homes in the Portland metro region, according to a study by the Earth Advantage Institute.

The annual study found that existing homes with a sustainable certification sold for 30 percent more than homes without one, according to sales data provided by the Portland Regional Multiple Listing Service. This finding is based on the sales of existing homes between May 1, 2010 and April 30, 2011 in Multnomah, Clackamas, Columbia, and Washington Counties in Oregon and Clark County in Washington.

The study also examined how newly constructed homes built to sustainable certifications performed, and found that they sold for 8 percent more than new non-certified homes in the same six-county area.

“This is important news for builders and home buyers alike,” said Dakota Gale, the sustainable finance program manager at the Earth Advantage Institute, in a press release. “While it must be noted that the data are supplied by real estate agents themselves through standard RMLS forms, and are based on averages, not comparables, we can still see a consistent trend that third-party certification continues to result in a higher sales price, even during the past year when home sales were down.”

There were several differences in the results between the counties as well. Clackamas had the largest difference between sales price of new certified and non-certified homes at 23.3 percent, whereas Clark County was the only area in the metropolitan area in which newly constructed certified homes did not sell for more than non-certified homes. That being said, existing certified homes in Clark County did outperform non-certified homes by selling for 29 percent more.

In analyzing this data along with the past three years, the Earth Advantage Institute identified two important trends. First, the market share of certified homes among all newly constructed homes remained consistent, with 18 percent of new homes in the Portland metropolitan area receiving a sustainability certification. Second, a price premium for certified homes as a group was observed each year, showing that people were willing to pay more for certified homes.